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Structure Evolution of Bulk Metallic Glass Zr_(52.5)Ni_(14.6)Al_10Cu_(17.9)Ti_5 during Annealing

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Journal of Materials Science & technology 2000年第4期16卷 357-361页

作者： Guo HE, Zan BIAN and Guoliang CHEN (State key laboratory of Advanced Metals and Materials, University of Science and technology beijing,beijing 100083, china) State key laboratory of Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

Bulk metallic glass Zr_52.5Ni_14.6Al_10Cu_17.9Ti_5 was prepared by melt injection casting method. Its glass transition and crystallization temperatures were determined by differential scanning calorimetry (DSC) to be 631 K and 710 K respectively. By analysis of X-ray diffractometry (XRD) and transmission electron microscopy (TEM ), the predominant crystallized phase of Zr_2Ni0.67O0.33 distributed on glass state matrix was detected after annealing at 673 K for 600 s. The transformation to Zr_2Ni_0.67O_0.33 and a small amount of ZrAl and Zr_2Cu took place after annealing for 600 s at temperature from 703 K to 723 K. With increasing annealing temperature from 753 K to 823 K, the amounts of ZrAl and Zr_2Cu increased, but the size of the crystals did not significantly change. The transformation to Zr_2Ni_0.67O_0.33 is interface-controlled, but is diffusion-controlled to Zr_2Cu and ZrAl. With increasing annealing temperature up to 200 K above T_x, the nanometer grains became very fine because of the increase of nucleation rate for Zr_2Cu and ZrAl.

关键词： Structure Evolution of Bulk Metallic Glass Zr Ti5 during Annealing Al10Cu Ni Cu

Influence of magnetic current on the ground state entanglement in an isotropic transverse XY chain

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Progress in Natural Science:Materials International 2007年第10期17卷 1147-1151页

作者： Liu Dan1,2 , Zhang Yong3 and Long Guilu1,2(1. key laboratory for Atomic and Molecular NanoSciences, and Department of Physics, Tsinghua University, beijing 100084, china 2. Center of Quantum Information Science and technology, Tsinghua national laboratory for information Science and technology, beijing 100084, china 3. Institute of Physics, School of Sciences, beijing University of Posts and Telecommunications, beijing 100876, china) key laboratory for Atomic and Molecular NanoSciences and Department of Physics Tsinghua University Beijing 100084 China Center of Quantum Information Science and technology Tsinghua National Laboratory for information Science and Technology Beijing 100084 China Institute of Physics School of Sciences Beijing University of Posts and Telecommunications Beijing 100876 China

We study the ground state entanglement in a three-qubit XY chain under the influence of a magnetization current. It is found that the ground state changes from a W state to a disentangled state as the magnetic field varies. When the Lagrange multiplier λ>3, namely under a strong magnetic current, the ground state holds onto a W state for a large range of the magnetic field strength. A phase transition to the magnetization-current phase occurs under a certain condition.

关键词： Heisenberg-XY chain magnetic-current phase transition.

Hydrogen Reduction:A Novel Method of Synthesizing Ultra-fine Chromic Oxide Powder

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Journal of Wuhan University of technology(Materials Science) 2010年第3期25卷 388-390页

作者：白玉兰 College of Science Qingdao University of Agriculture

The ultra-fine chromic oxide powder was prepared by a novel gas-solid reduction ***2CrO4 was firstly reduced with hydrogen at 400-600 ℃.The obtained reduction products,mainly the mixture of NaCrO2 and sodium hydroxide（NaOH）,were converted into chromic oxide through hydrolysis followed by *** obtained chromic oxide product was characterized by powder X-ray diffraction（XRD） and *** results show that the hydrolysis process of sodium chromite is the key step and lower reduction temperature helps intensify the hydrolysis process.

关键词： chromic oxide gas-solid reduction ultra-fine powder

Propagation characteristics of converted refracted wave and its application in static correction of converted wave

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Science china Earth Sciences 2008年第S2期51卷 226-232页

作者： LIU Yang1,2 & WEI XiuCheng3 1 State key laboratory of Petroleum Resource and Prospecting,china University of Petroleum,beijing 102249,china 2 CNPC Geophysical Exploration key laboratory,china University of Petroleum,beijing 102249,china 3 Exploration and Production Research Institute,SINOPEC,beijing 100083,china china Univ Petr State Key Lab Petr Resource & Prospecting Beijing 102249 Peoples R China china Univ Petr CNPC Geophys Explorat Key Lab Beijing 102249 Peoples R China SINOPEC Explorat & Prod Res Inst Beijing 100083 Peoples R China

Three-component seismic exploration through P-wave source and three-component geophone is an effective technique used in complicated reservoir exploration. In three-component seismic exploration data processing,one of the difficulties is static correction of converted wave. This paper analyzes propagation characteristics of non-converted and converted refracted waves,and discovers a favor-able condition for the formation of converted refracted wave,i.e. the velocity of overlaying medium S wave is much lower than that of underlying medium S wave. In addition,the paper proposes the static correction method of converted wave based on PPS converted refracted wave,and processes the real three-component seismic data with better results of static correction of converted wave.

关键词： PPS converted refracted wave converted wave static correction

Anomalous magnetotransport in LaMn_(1-x)Te_xO_3

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Science china(Physics,Mechanics & Astronomy) 2009年第7期52卷 987-992页

作者： TAN GuoTai1,2, CHEN ZhengHao3 & ZHANG XiaoZhong4,5 1 key laboratory of Beam technology & Materials Modification of the Ministry of Education, Institute of Low Energy Nuclear Physics, beijing Normal University, beijing 100875, china 2 beijing Radiation Center, beijing 100875, china 3 laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, beijing 100080, china 4 key laboratory of Advanced Materials of the Ministry of Education, Department of Materials Science and Engineering, Tsinghua University, beijing 100084, china 5 beijing national Center for Electron Microscopy, Tsinghua University, beijing 100084, china 1. key laboratory of Beam technology & Materials Modification of the Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing 100875 China 2. beijing Radiation Center Beijing 100875 China 3. laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China 4. key laboratory of Advanced Materials of the Ministry of Education Department of Materials Science and Engineering Tsinghua University Beijing 100084 China 5. beijing national Center for Electron Microscopy Tsinghua University Beijing 100084 China

The LaMn1-xTexO3+δ (x=0.1, 0.2, 0.3) were synthesized using solid-state reaction method for the first time. X-ray photoemission spectrum (XPS) shows that in the samples the Te ions have a valence of Te4+, and Mn3+ ions are partly converted into Mn2+ and Mn4+ due to the excess oxygen and Te doping. The magnetotransport associated with Mn2+, Mn3+ and Mn4+ was investigated. The experimental results show that the samples are insulator at 0 T when the amount of Mn3+ is much larger or less than the sum of Mn2+ and Mn4+; by contrast, the samples display metal to insulator transition with increasing temperature when the amount of Mn3+ is close to the sum of Mn2+ and Mn4+. These anomalous magnetotransport behaviors were analyzed in the frame of the double-exchange (DE) mechanism.

关键词： colossal magnetoresistance La-Te-Mn-O magnetotransport

Fuzzy interface treatment in Eulerian method

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Science china(Technological Sciences) 2004年第5期47卷 550-568页

作者： NING Jianguo1 & CHEN Longwei1,2 1. national key laboratory of Protection and Control of Explosive Disaster, beijing Institute of technology, beijing 100081, china 2. The Faculty of Land Resource Engineering, Kunming University of Science and technology, Kunming 650093, china Correspondence should be addressed to Ning Jianguo 1. national key laboratory of Protection and Control of Explosive Disaster Beijing Institute of Technology 100081 Beijing China 2. The Faculty of Land Resource Engineering Kunming University of Science and Technology 650093 Kunming China

In this paper, we incorporate fuzzy mathematics approach into the Eulerian method to simulate three dimensional multi-material interfaces. In particular, we propose a fuzzy interface treatment for describing interfaces, designing transport plans, and computing transport quantities. Using a set of three-dimensional inviscid isothermal elastic-plastic hydrodynamic equations, we simulate shaped charge jet in different filled dynamite structures. Strain and stress have been under consideration in simulations. Numerical results demonstrate that the fuzzy interface treatment is correct and efficient for three-dimensional multi-material problems.

关键词： Eulerian method, multi-material, fuzzy interface, shaped charge jet, three-dimensional numerical simulation.

A study on compressive shock wave propagation in metallic foams

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Science china(Physics,Mechanics & Astronomy) 2010年第2期53卷 279-287页

作者： WANG ZhiHua1,2,ZHANG YiFen2,REN HuiLan1 & ZHAO LongMao2 1 State key laboratory of Explosion Science and technology,beijing Institute of technology,beijing 100081,china 2 Institute of Applied Mechanics and Biomedical Engineering,Taiyuan University of technology,Taiyuan 030024,china 1. State key laboratory of Explosion Science and technology Beijing Institute of Technology Beijing 100081 China2. Institute of Applied Mechanics and Biomedical Engineering Taiyuan University of Technology Taiyuan 030024 China

Metallic foam can dissipate a large amount of energy due to its relatively long stress plateau,which makes it widely applicable in the design of structural crashworthiness. However,in some experimental studies,stress enhancement has been observed when the specimens are subjected to intense impact loads,leading to severe damage to the objects being protected. This paper studies this phenomenon on a 2D mass-spring-bar model. With the model,a constitutive relationship of metal foam and corresponding loading and unloading criteria are presented; a nonlinear kinematics equilibrium equation is derived,where an explicit integra-tion algorithm is used to calculate the characteristic of the compressive shock wave propagation within the metallic foam; the effect of heterogeneous distribution of foam microstructures on the shock wave features is also included. The results reveal that under low impact pulses,considerable energy is dissipated during the progressive collapse of foam cells,which then reduces the crush of objects. When the pulse is sufficiently high,on the other hand,stress enhancement may take place,especially in the heterogeneous foams,where high peak stresses usually occur. The characteristics of compressive shock wave propagation in the foam and the magnitude and location of the peak stress produced are strongly dependent on the mechanical properties of the foam material,amplitude and period of the pulse,as well as the homogeneity of the microstructures. This research provides valuable insight into the reliability of the metallic foams used as a protective structure.

关键词： aluminum foam heterogeneous intensive pulse loading stress enhancement

Security model and modular design of fair authentication key exchange protocols

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Science china(Information Sciences) 2010年第2期53卷 278-287页

作者： FENG DengGuo & CHEN WeiDong State key laboratory of Information Security, Institute of Software, Chinese Academy of Sciences, beijing 100190, china 1. State key laboratory of Information Security Institute of Software Chinese Academy of Sciences Beijing 100190 China

It is traditionally assumed that the legal two parties in authentication key exchange (AKE) communications are both credible. However, in more and more network applications nowadays, it is often required that such protocols be run under the circumstances where ones do not trust in each other. Therefore, in this paper we propose the idea of fair authentication key exchange (FAKE), which has not only the basic properties of AKE protocols, but also some new properties: the "session proof" embedded in the input of protocols by the customer; and if not revealed, the protocols have the deniability, otherwise the transcript of protocol is binding for the identifications. Such a method is capable of solving the contradiction between protecting privacy and the dissension on network service. Then the security model of FAKE protocols is formulated systematically and a flaw of the security model of current signature schemes proposed by Kudla is also corrected. Finally, a kind of FAKE protocol based on current signature schemes is designed and the mBJM-AK security, conditional deniability and fairness of FAKE protocols are proved in the random oracle model.

关键词： authentication key exchange protocols deniability fairness concurrent signature provable security

Quasi-secure quantum dialogue using single photons

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Science china(Physics,Mechanics & Astronomy) 2007年第5期50卷 558-562页

作者： YANG YuGuang1,2 & WEN QiaoYan31 College of Computer Science and technology, beijing University of technology, beijing 100022, china 2 State key laboratory of Information Security, Graduate University of the Chinese Academy of Sciences, beijing 100049, china 3 School of Science, beijing University of Posts and Telecommunications, beijing 100876, china College of Computer Science technology Beijing University of Technology Beijing 100022 China State key laboratory of Information Security Graduate University of the Chinese Academy of Sciences Beijing 100049 China School of Science Beijing University of Posts Telecommunications Beijing 100876 China

A quasi-secure quantum dialogue protocol using single photons was proposed. Different from the previous entanglement-based protocols, the present protocol uses batches of single photons which run back and forth between the two parties. A round run for each photon makes the two parties each obtain a classical bit of information. So the efficiency of information transmission can be increased. The present scheme is practical and well within the present-day technology.

关键词： quantum dialogue, single photon, quantum secure direct communication